Composting for the Home Gardener; Basics of How to Compost for Rich Soil Full of Enriching Nutrients

byAlex Averin

Composting for the Home Gardener:

I have had a backyard garden for about 15 years, but I have not always made additions to my outside soil via composting methods. Since doing so, I have been pleased with the results. Composting can be beneficial in a number of ways and throughout the rest of this post, I will describe composting methods and the benefits of utilizing these methods.

Composting Overview:

Composting is a way for the home gardener to add nutrient-rich humus to the outside soil which will act to fuel plant growth and restore key elements to soil that may be nutrient depleted. In general, composting is a process of breaking down organic waste such as food waste, leaves and trimmings and even coffee grounds into a useful humus-like substance so that the end-product acts as a valuable soil additive to enhance plant growth.

Basic Composting Materials: Organic Browns and Greens can be included in the compost pile. Browns include leaves and wood chips and these items are high in carbon. Greens include grass clippings and kitchen scraps and these items are high in nitrogen.

All organic matter will eventually decompose, but not all organic matter will decompose and result in compost that will benefit the garden. Water, nitrogen, carbon and oxygen all play a role in the break-down of material in a compost pile which can result in a well balanced mixture of organic compost that can be added to outside soil to support healthy plant growth. Multiple variables must be considered during the composting process to ensure a viable end-product.

Composting Variables that Need to be Considered:

Basic Elements of Composting:

Food – organic materials put into compost pile

Water – pile should be somewhat moist but not saturated

Air – oxygen is needed to support the biological decomposition of organic wastes

All organic matter will decompose, but certain steps should be taken to ensure that the end-product is something that will be beneficial.

Space Needed:

My compost piles are kept within a rectangular fence enclosure that I have built under an overhanging roof attached to my barn. Remember, too much moisture can be a bad thing for your compost pile and so you need to have it protected from excessive rains. My enclosure is approximately 3′ x 5′. I often add to my compost pile in layers. Greens and browns are mixed and spread in a layer into the compost enclosure. Well water is added if necessary to maintain appropriate moisture levels.

Temperature:

Temperature is one variable that needs to be considered during the composting process. The lower the outside temperature, the longer the composting process. Temperatures that are too low can ultimately interrupt the composting process so that a useful end-product is never reached. Winter composting can be difficult since the process of decomposition may halt altogether in freezing temperatures. During composting, the temperature needs to be high enough to kill pathogens. Hot temperatures encourage and stimulate microbial action which supports the decomposition. Higher temperatures allow the bacteria to perform exothermically to act as a catalyst for decomposition. Cooler temperatures get in the way of this process. Since I live in the Northeast, the spring, summer and fall months are best for sustaining temperatures that excite the reactions necessary to complete the compost process. Regardless of the outside temperature however, I continue to add to my compost pile. Proper decomposition will continue once temperatures are warm enough outside.

Decomposition of organic material happens best in the thermophilic range. Composting material needs to sustain an internal exthermo-biological reaction that push temperatures into the thermophilic range. This range of temperatures is 135 – 160 degrees Fahrenheit. This is the optimal range. Internal temperatures below this range will slow or halt the process and temperatures above this range are also undesirable and inefficient. If the compost pile internally maintains this ideal temperature range, the heat efficiently destroys pathogenic organisms, flies and weed seeds while providing better decomposition.

Maintaining an optimal temperature of the compost pile depends on other factors as well. The surrounding ambient temperature outside is a factor, as is the moisture content of the compost pile, the degree of aeration, and the specific contents of the compost pile.

Deeper piles of compost will cause higher temperatures and better temperature distribution. So, if you find that the heat of your compost pile is exceeding the optimal range, one option is to break the pile into two separate areas which should bring the internal temperature down. One should also keep in mind that aeration is needed to maintain aerobic conditions in the compost pile. Aeration is needed for maintenance of acceptably high temperatures. Aeration (which happens when the material being composted is turned) will support high temperatures and also act to support faster decomposition that gives off little to no odor. Be sure that the material on the outside of the pile gets turned into the center of the pile so that it too can be subject to the high temperatures needed for proper decomposition.

Turning Compost for Aeration and Moisture Content:

For most back-yard gardeners like my myself, turning the compost pile is a chore that I do by hand with a pitch fork. How often I turn the compost pile depends on the temperature, moisture content and the material in my pile. I have found that turning my pile every three or four days elevates temperature as opposed to turning every two weeks. The better aeration supports the decomposition of material in the pile and ultimately reduces the time it takes for the pile to decompose properly. If your pile consists of mixed items and refuse, as does mine, turning at three day intervals is likely a good schedule to follow. A mixed pile that includes trimmings and grass cuttings and paper is likely to have a moisture content somewhere between 40 and 60 percent. Turning the pile at three day intervals is proper and will help the pile to decompose efficiently.

If you turn the pile at three day intervals and you notice a foul odor, then turn the pile daily for a week or so until the odor disappears. Then return to turning the pile every three days. The foul odor is a sign of a compost pile going anaerobic. This can be remedied relatively quickly though by increasing the frequency of turning. Daily turning can also be useful when controlling fly breeding. The ultimate goal here is to maintain aerobic conditions, avoid anaerobic conditions, and maintain internal pile temperature levels that fall within the optimal range noted above.

When is the Compost Finished:

When a compost pile is ready to be used, it will look rich and dark, and will have a smell that is similar to earth and a texture that is loose and crumbles apart through your fingers. Another rule of thumb that I use is internal temperature. When the compost no longer produces heat, decomposition may be complete. If your compost pile has been turned regularly and it is no longer producing heat, then it is just about ready. I will let my pile rest for a week or so while any remaining heat dissipates so that organisms such as worms can move back into the compost pile. This action ultimately improves that end-product.

Testing the Compost:

It is important to make sure that your compost pile has matured appropriately because immature compost contains substances that have not been “spent” which can ultimately hurt plant growth if it is mixed with the garden soil. Specific factors that need to be considered when determining compost maturity include temperature, pH level, as well as microbial activity. Home tests can be acquired online for testing compost maturity. I have not used a home testing kit, but resources for home testing compost can be reviewed at the Florida Online Composting Center.

Screening the Compost:

I should also note that I do not regularly screen out my compost. Items that are easy to see and pick out, like fruit pits and corn cobs, will be discarded by hand. I choose not to do the extra step and work of screening, but if you choose to do this step, developing a screening process is not too difficult. A few pieces of wood for a frame and a square screen over the wheelbarrow will work adequately for this job.

Remember, the finished compost should look dark, rich and uniform. It should contain a dark soil-like humus that gives off an earthy odor.

Benefits Associated with Composting for the Backyard Garden:

I have utilized compost in varied ways for years and find that it not only aids in the soil’s ability to retain and drain water, but it gives my plants an additional boost without the burn that some harsh chemical fertilizers will produce. Composting adds additional nutrients to your soil which is then utilized by plants.

Microscopic organisms in the compost help to aerate the soil and break down any organics which ultimately benefits plants.

Reusing and Recycling Kitchen and Yard Waste – Many scraps from the kitchen can be utilized for in the composting process. Key items that I throw into my compost area include coffee grounds, tea bags and grass clippings (I do not add chemical to my lawn), dried leaves, as well as scraps from fruits and vegetables. This practice is not only good for the backyard garden, but it is also good for the environment since it reduces the waste we send off to the local landfills.